Tire tread depth for semi-trucks: Breakdown for new drivers

Estimated reading time: 2 minutes

Ensuring your semi-truck's tire tread depth meets safety standards is crucial for maintaining road safety. Whether you're a seasoned truck driver or new to the job, knowing regulations and how to check your tires can help ensure a safer driving experience.

Below, we’ll cover regulations regarding tire tread depth for semi-trucks and walk you through the steps to check it effectively.

What is tire tread depth?

Tire tread depth refers to the distance between the top of the tire's rubber to the bottom of its deepest grooves. Tread depth is measured in thirty-seconds of an inch increments.

The deeper the tread depth on semi tires, the better they will grip the road. This is essential for several reasons, including:

• Safety: Ensuring better traction on the road, especially in adverse weather conditions.
• Performance: Maintaining optimal handling and braking performance.
• Compliance: Adhering to legal requirements to avoid fines and penalties.

Drivers should check their tires' tread depth, as well as pressure and overall condition, during their pre-trip inspection.

Semi-truck tire tread depth regulations

According to the Department of Transportation, the guidelines for minimum tread depth on a semi-truck are:

• Steer tires: Minimum tread depth of 4/32 of an inch.
• Drive and trailer tires: Minimum tread depth of 2/32 of an inch.

Tires that fail to meet these criteria are considered unsafe for the road. They may not only lead to fines, but may increase the risk of accidents due to decreased traction. It is also important to regularly check your state’s regulations to ensure you remain compliant.

See for yourself: Tire tread test walkthrough with an expert 

Learn how to check the tread depth of your tires with the help of Schneider Training and Development Administrator, Brian Johnson. 

How to check semi-truck tire tread depth

Checking your tire tread depth is easy and can prevent potential issues down the line. Here’s how you can do it:

1. Using a tire gauge:

The main way to check your tread depth is by using a tire tread depth gauge:

• Place the probe of the gauge into the tread groove.
• Make sure the gauge is perpendicular to the tire to get an accurate reading.
• Press the gauge’s shoulders flat against the tread. This will push the scale inside the gauge’s body outward, showing the tread depth.
• Pull it out and check the reading.

To get an accurate reading, check the tire tread depth in multiple spots around each tire, paying close attention to both the inner and outer edges. Using a tire tread depth gauge gives you a precise measurement and ensures your tires are safe and legal.

2. Using the penny test:

If you don’t have a tire tread depth gauge, you can use a penny to perform a quick check:

• Hold a penny so Lincoln’s head is facing down.
• Choose a tread groove and insert the penny.
• If any part of Lincoln’s head is covered by the tread, your tires are probably above the minimum. But, if you can see the top of Lincoln’s head, the tread depth does not meet the necessary requirements.

While the penny test is a useful check, it's not as precise as using an actual tire tread depth gauge and should not be your sole method of inspection.

What to do if tread depth is too low

If your tire tread depth is below the minimum, it's important that you replace the tires as soon as possible. This will help to ensure the safety of your truck and compliance with regulations.

Make sure to review your company guidelines or speak with your leader for more information about addressing tire issues.